curtiss



(No Model.) 2 Sheets-Sheet 1.

R. M. CURTISS.

BLBGTRIG-SAPBTYYDEVIGB POR BLEVATORS. N0.266,107. Patented Oct. -17,1882.

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. 2 Sheets-Sheet; 2Q

Patented Oct. 17. 1882.

R. M. CURTISS. ELECTRIC SAFETY DEVICE ECR ELEVATCRS. No. 266,107.

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'III Il UNITED STATES PATENT OFFICE.

ROBERT M. CURTISS, OF BROOKLYN, NEV YORK.

ELECTRIC SAFETY DEVICE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 266,107, dated October17, 1882. v

(No model.)

.To all whom it may concern:

Be it known that I, RoBERT M. CURTISS, of Brooklyn, Kings county, NewYork, have invented certain new and useful Improvements in SafetyDevices for Elevators or Hoists, of which the following is aspecification.

My invention relates to safety appliances connected with the movable caror cage of elevators and with the hoisting machinery operating it,whereby the safety-catches of the car will be released against theguides to uphold the car in case the hoisting-cable or any part of thehoisting machinery should become strained or broken, or in case thecable should become vslacked by the jamming of the car during thedescending movement, even though no break or injury may have occurred inthe machinery.

In a former patent issued to nie June 3,1879, No. 216,024, I employed anelectric circuit passing through the cable and including anelectro-magnetic detent in the car, which controlled the safetycatches,so arranged that on the breaking or straining of the cable the electriccircuit would become broken, the magnetic detent relaxed, and thecatches thereby instantly released to uphold the car. My presentinvention embodies this system, and is an improvement on my formerpatent. In my present improvement I extend a frangible electricconductor through the parts of the hoisting engine or machinery whichare subjected to the working strain, and this conductor may also becontinued through the hoisting-cable to the magnetic detent whichcontrols the safety-catches, the conductor being of course arranged in anormallyclosed circuit constantly energized by a battery or otherelectric source, so that if any part of the hoisting apparatus becomesstrained or broken-such as thecable or thepistomcylinder,shafts,sheaves,or bear ings of the hoistingengine-the frangible conductor whichtraverses these parts will become simultaneouslybroken, thus instantlywhich the car is suspended passes loosely through a socket in the hangeron top of the car, and a collar or shoulder fixed to the end of thecable seats against the under side of the socket, and thus suspends thecar, and the electrical circuit is so arranged as to pass through thecontact-faces of said collar and socket, so that in case the cableshould ever become slacked during the descending movement by the jammingof the car in the guides these contact-faces will become relaxed orseparated, thereby breaking the electric circuit and releasing thecatches so as to safely sustain the car, and thus prevent thepossibility of its becoming released and plunging down the shaft duringthe slack in the cable, as has frequently occurred heretofore with greatdamage.

My invention therefore consists mainly in the features here outlined,and also embodies several minor features in the special construction andarrangement of parts, as hereinafter fully set forth.

1n the drawings, Figure 1 presents a sectional elevation of an ordinaryelevating apparatus, including the car, hoisting-en gine, &c., providedwith my safety appliances. In this ligure the lioisting-engine ispresumed to be ot' the hydraulic kind, arranged horizontally at the baseofthe shaft, the piston of the engine being arranged to operate a seriesof movable sheaves of a compound pulley, over which the cable passes inloops and extends to the car in the well-known manner, which it isunneeessary to describe in detail. Any other kind of hoisting-engine,however, may of course be employed. Fig. 2 is an enlarged detail view ofthe top of the car to which the cable connects, and which is providedwith the suspensory electric contacts, which separate on the slacking ofthe cable, and which also carries the safety catches or pawls to engagewith the guides, and the electro-magnetic deten't which holds them outotengagement while the circuit is closed and releases them when thecircuit is broken. Fig. 3 is a detail of the suspensory contacts bywhich the cable connects with the car, showing the contacts separated,as occurs when the cable slacks. Fig. Ll. is a detail of thesafety-catches in plan view. Fig. 5 presents a sectional elevation of avertical ICO form ot' hoisting-engine, showing my safety electriccircuit applied thereto in a somewhat different manner from Fig. 1, thecar being omitted in this view. Fig. Gis a plan view of the under sideof the car in Fig. 1, showing the arrangement of'saf'ety-catches andelectromagnetic detent thereon. Fig. 7 is a similar view with themechanism slightly modified. Fig. S is a perspective view of an ordinaryhoisting-drum ot' a winding-engine, showing my safety electric circuitapplied to the shaft and cables thereof.

Referring to Figs. 1, 2, and 6, l have shown the car as provided withsafety-catches a a b b, of ordinary form, respectively at the top andbottom, which, when released, will engage with the usual ratchcts, c, onthe guides d to sustain the car, but ofcourse either the top or bottomset of catches may be used alone, it' preferred.

In Fig. 1, e indicates a battery or other suitable source ot'electricity, one pole of which connects by the wire f to aconducting-strip, f', which extends along the cross-head guides of thehoisting-engine, and is insulated therefrom. A brush,g, which is carriedbythe crosshead or piston-rod of the engine, bears on this conductor,and from this brush an insulated wire, g', extends through thepiston-rod into the piston-head, being laid in a suitable bore or groovetherein, and returning similarly through the rod, as shown by the dottedline, connects to a second brush, h, which is carried by the cross-headand bears upon a second insulated conductor-strip, t,parallel with theother one. From the conductor-strip h a wire, It, extends and passesaround the journal-box ofthe ixed sheaves of the engine, and thenceconnects to the fixed end of the hoisting-cable t'. The circuit thencecontinues through the hoisting-cable, either directly through the massof the cable or through an insulated wire embodied therein, and thecurrent thus Hows toward the top ot' the car, as indicated by thearrows. Now, the' suspending or car end of the cable passes looselythrough a socket, j', in the suspending loop or bail j, which rises fromthe top of the car, and the extremity ot' the cable is tixed in theholder or collar lc, which seats against the under side of the socket ofthe bail j, so that the car is thus suspended by the contact of thecollar lc with the base of the socket j. Now, these suspcnsorycontacting faces' are arranged in the electric circuit, for, as shown inFigs. l and 2, the current, in passing from the collar on the end of thecable, passes through the contacting face on4 the base ot' the socket,and a continuing circuitwire, l, extends from this face, and, descendingto the bottom ofthe car, as seen in Fig. 1, connects with the end of thecoils ot' an electromagnet, m', on the bottom of the car, as seen bestin Fig. 6. From the opposite end of these magnet-coils the circuit iscontinued by a wire, l', up through the opposite side of the car, asseen in Fig. l, and connects with one end of a second electro-magnet, m,arranged on the top of the car, (shown also in Fig. 2,) and from theopposite end of this magnet a Wire, Z, leads to a brush, n, on the topof the car, which brush bears on a conducting-strip, n', which extendsup along the guides d, and by which the current returns to the oppositepole of the battery by the wire n, which is connected to the base ot'the strip n', thereby completing the circuit.

Now the upper safety-catch or pawl-spring, a, is tlexed and held out ot'engagement, as shown best in Fig. 2, by the winding cfa cord, o', aroundthe middle of a small winding or setting drum, 0, Figs. 2 and 4, whichdrum is held stationary by the grasp ot' double brakebands o, which aretightened by the depression ofthe lever q. When the lever q is thusdepressed it is there held by a detent-hook on an elbow-lever, p, whichforms the armature, or is connected with the armature, of the magnet min a manner similar to what is shown in my former patent. It will hencebe seen that lwhile the magnet is energized by a closed circuit itsattraction will hold the parts in the set position shown, therebyholding the safety-catches out of engagement; but if the circuit becomesbroken the magnet will become inactive, and thus release the parts andallow the catches to spring into engagement. In a similar manner thecatches or bolts h b on the under side ofthe car (see Fig. 6) are heldout ot' engagement against the stress of springs b b by the grasp of aforked lever, b, which embraces collars on the meeting ends ot' thebolts, and this forked lever is held in its engaging position by thearmature -detent p, which is retained by the attraction ofthe magnet m',when in a closed circuit, in the same manner as that just described, sothat on the breaking ot' the circuit the bolts b b will be released toengage with the guides, as will be readily understood.

It will therefore be seen that by my invention the entire elevatingapparatus is, so to speak, enveloped in an electric safety web orcircuit, which traverses all parts or most ot' the parts which aresubjected to the working strain and wear, so that in the event ofany ofthese parts breaking-for instance, if the piston -head should becomeseparated from the rod or the rod severed, the cross-headdetached orbroken, the shaft or journal-boxes ot' the sheaves severed, or theframe-work of the engine fractured, or the cable rent-this electriccircuit will become simultaneously broken and the safety-catchesinstantaneously released, and the car thus held safely in the guides,before any damage could result to the occupants by such break orinjury.A This invention hence presents a notable safety device, for ithas ot'ten happened that while the cable has remained uninjured somepart ot' the hoistingengine has broken, and thus allowed the car tofall, while its cable and safety-catches remained unimpaired, for thecommon safetycatches act only by a great relaxation or breaking ot' thecable, and where there is suilicicnt ICO IIO

strain oii the cable to keep the safety-catches out, yet not sufficientto stop or retard the car, as would be the case with a break in theengine, the safety-catch will not act and the car will falldisastroiisly, as has occurred on several occasions. This, however, iscompletely prevented by my improvement, for by its means a break in anyworking part of the hoistingengine, as well as in the cable, willrelease the clutches and sustain the car with electrical quickness andcertainty.

It will be noted on reference to Fie'. 1 that the circuit also passes upthrough each side of the car from the bottom, and that the circuitcontrols safety-catches both on the top and bottom of the car. Hence,it' the car should break apart in any manner, as not uncommonly happens,say if the top part should become torn away from the bottom, or viceversa, the circiiit-wires will in either case become broken and thesaiety-catches'on the bottom ofthe car instantly released, thus safelysustaining the door of the car and the passengers which may be in thecar. Now, on the other hand, although no pait of the hoisting appa.-ratns should break, assume that during the descending movement the carshould become jammed in the guides from any cause,the cable would thenof course continue to be paid out by the retiirn-stroke of the engine,and .thus form an extensive slack, and it' the car should during thisslack become again loosened in the guides it would suddenly plungedownward or fall, and thus be likely to do great damage. It will beseen, however, that my invention completely provides against the chanceof this accident, for if any slack forms in the cable during the descentofthe car the collar 7c on the end of the cable (see Figs. 2 and 3) willseparate or recede from the under side of the socketj', and thus breakthe electric circuit, and thereby release the catches andpreventthecarf'rom falling,thusprovidingagainst accidents under almostall circumstances.

In Fig. 2 the suspensory contacts are shown in contact, but arerepresented as separated in Fig. 3 by the formation ot' slack in thecable. In order to insure the certain separation ot' these contacts onthe formation of slack, a strong spring, lo, fixed at one endto thecable and at the other end to the suspending-bailj, tends constantly topull the collar-ed end ofthe cable away from the socketj, which it willdo as soon as the cable becomes relieved ot' the weight of the car. Theweight of the slack cable would of course ot' itself tend to separatethe contacts; but the spring k assists this action and renders it morecertain, as will be understood.

It may be noted that, if desired, the downward motion of the collar onthe end of the cable when the. cable becomes slacked might be arrangedto close an electric circuit normally open, which when so closed wouldenergize an electro-magnet to release the safetycatches, this beingsimply a reverse modication of that shown but I prefer the close-circuitarrangement sct forth.

In Fig. l the cable may, if desired, be omitted from the electriccircuit and the circuit completed through the conductor-strips on theguides; or, again, the conductor-strips on the guides may be dispensedwith, and the circuit may then be advanced and returned through thecable by advancing and returning wires insulated from each other, asshown in my former patent, and alsoillustrated in Figs. 3 and 5 of thepresent drawings. In Fig. 5 the current iiows from one pole of thebattery to a conducting-rod, r,on which slides an arm which projectsfrom the cross-head, through which arm the current passes and descendsthrough one piston-rod, thence crosses through or above the piston-head,rises through the second piston-rod, thence passes through the shaft ofthe movable sheave to a second brush carried by asecond arm on thecross-head, and bearing on a second conductingrod, r', and from this rodthe current tiows through an insulated wire in the cable, passes throughthe magnet m or m', or both, and returns through another wire in thecable, as indicated by arrows. which return wire, as indicated by s inFig. 5, is extended from the hxed end of the cable, passes across theupper head of the enginecylinder, down along one side of the cylinder,across the bottom head, up the opposite side of the cylinder, and thenceconnects to the opposite pole ot' the battery, thus completing thecircuit. The circuit-wires should ofcourse be covered or insulatedthroughouttheircoiirse, and insulation should be introduced wherevernecessary to insure the passage of the current, as described andindicated. rlhe circuit is preferably continued through the piston-rodsby means of insulated wires laid in grooves cut therein and covered upflush with the cylindrical surface of the rods. The circuit wires orconductors which traverse the parts of the car and hoisting machinerywhich are liable to become broken or fractured by the working strainshould be stretched upon and fastened along the parts of the car ormachinery along the couise of the circuit, and while sufficiently largeto convey the necessary current these wires should be sufficientlyfragile so as to become easily broken by any stretch. stra-in, orfracture in the parts of the car or machine on which they are fastened.By this means l insure the breaking of the circuit and the releasingofthe safety-catches, as described, when any dangerous stretch, strain,or fracture occurs in the car or machinery, although no actual break mayhave yet occurred, thus forming a most vigilant and valuable guard forthe prevention of damage to the car or'its contents.

In Fig. l I have represented an incandescent electric lamp, t, in thesafety-circuit to light the car, and this may be extinguished and thrownout of circuit, when desired, by a switch, which will thus cut the lampont of ac- ICO IOS

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tion without breaking the safety-circuit. The lamp, however, ispreferably placed in a separate circuit. which can be advantageouslycoinpleted by brushes carried by the car bearing on conducting-strips onthe guides, similar to what is shown atn a in Fig. l.

Fig. 7 shows a slight modification of the mechanism ot' Fig. 6 on theunder side of the car. In this case the safety-bolts b b connect byclamps to crank-pins on a brake-disk, o, on which a brake-baud istightened by a lever, q, and held by the armature-detent, saine as inFig. 2.

Fig. 8 shows one way of applying my electric safety-circuit to anelevator which operates the car from a winding-drum. In this case twoparallel cables are supposed to be used. rIhe two poles of the batteryconnect with two brushes, which bear upon insulated conducting-rings u aon the projecting end of the drum-shaft. Insulated wires extend throughthe shaft from the respective rings, and connect respectively with thefixed ends of the two cables, the circuit passing thence through a wirein one cable, through the detent-magnets on the car, as beforedescribed, and thence returning through t-he wire in the other cable, asindicated by the arrows.

I do not of course confine myself to the precise mechanicalconstructions shown in which my invention is embodied, as the mechanicalform of the parts might be varied considerably without departing fromthe principle. I would also remark that I prefer to have the magnetswhich control the detents and safety-catches arranged upon the car, asshown; vet the magnets might be arranged apart from the car, butoperatively connected with the catches on the car, if desired.

It will be seen that the conductor-stripsf h and brushes g h in Fig. lform an extensible or movable conductor between the portion of thecircuit in the movable part of the machine a-nd the fixed parts. Anyother form of extensible conductor might of course be used between theseparts-for instance, a spiral spring or a toggle-loop of wire whose slackwould be taken up at the middle by a pulley-weight.

Instead ofthe conductors being iu the form of continuous or solid wirestraversing the parts of the car or motor, which are liable to becomebroken, the conductor may be in the form of sectional strips, bearing oneach other and adapted to become separated, so as to break the circuitwhen the parts traversed become broken; but a continuons fragileconductor is preferable.

A close hood or cover, i/is placed over the detent mechanism at the topofthe car to proteetit from dust or injury. The mechanism at the bottomof the car may be similarly covered.

What I claim isl. The combination, with a hoisting or elevatingapparatus, of a frangible or separable electric conductor traversingportions of the hoisting machine or motor which are subjected to theworking strain or wear, and arranged in a closed electric circuitincluding an electromagnetic detent which controls safetycatchesarranged to uphold the car, whereby the breaking of the parts of themotor so traversed will break the electric circuit, and thereby relaxthe magnetic detent and release the safety-catches to uphold the oar,substantially as herein set forth.

2. In an elevating apparatus, the combination, with an engineconstructed with a working cylinder and a pistou operatively connectedwith the car through the intervention ot'a pulley and cable, or theirequivalent, of a fran gible or separable electrical conductor traversingthe piston rod or other working parts of the engine, a closed electriccircuit in which said conductor is included, an electro-magnet formingpart of said circuit and arranged to control Vsafety-catches to upholdthe car, so arranged that on the breaking ofthe electric circuit thesaid magnetacts to release the catches to sustain the car, substantiallyas herein shown and described.

3. In a hoisting apparatus, the combination, with uthe car and thehoisting-cable or equivalent t'rom which the car is suspended, and withsafety catches to uphold the car, of an electric circuit passing throughthe contacts by which the car is suspended from the cable, and anelectro-magnet in said circuit arranged to control the safety-catches,whereby the slacking` of the cable will separate said contacts, breakthe circuit, and release the safetycatches, substantially as herein setforth.

4. In an elevator, the combination, with the car and the hoisting-cablefrom which the same is suspended, and with safety-catches arranged touphold the car when released, ot' an electricjcireuit and a magnet insaid circuit controlling the safety-catches, with the end of the cablearranged loosely in the suspendin g-socket on the car and capable ofplay therein when slacked, and so connected with said electric circuitthat the relaxation ormovemcnt of the cable end in the suspending-socketwill make or break said circuit, and thereby operate said magnet so asto release the catches and sustain the car, substantially as herein setforth.

5. The combination, with an elevator car or platform provided withsafety catches arranged to uphold the car when released, of a frangibleor separable electric conductor traversing the car or portions of thecar, and arranged iu a closed electric circuit, with an electro-magnetin said circuit arranged to control said satety-catches, whereby thebreakin g or straining ofthe car will break thc electric circuit andrelease the safety-catches, and thereby hold or sustain the broken car,substantially as herein set forth.

ROBERT M. CURTISS.

Witnesses:

JNO. E. GAVIN, GHAs. M. HIGGINS.

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